Seeking advise re: the front end before I start taking things apart - Page 2 - PeachParts Mercedes-Benz Forum

RML · #16 07-24-2011, 06:58 PM

The car had a front end alignment after a repair last summer, so I am going under the assumption that it is not an alignment problem, but a wear problem on one of the steering components. Besides, the problem was there before and after the alignment. It is just that it has gotten worse in the past few months of driving. This input is very helpful. As far as wear patterns on the tires go, they are fairly new and do not have much wear, so I cannot tell much from that. My first point of investigation is going to be the upper control arm bushings.

leathermang · #17 07-24-2011, 07:36 PM

Quote:

Originally Posted by scottmcphee

Too much toe-out (actually, any toe-out) on the front wheels can cause this wander. It doesn't take much. Quick alignment check will rule this out. You want zero toe / dead straight at the front. Well, maybe slight toe-in if not using a road force bar when doing alignment.

Yes, lets suggest slight toe in.... what this allows is the slight wear on all the parts which control the direction the tires ' look' to be pulled outwards by centrifugal force to the straight position...

In the 123 Passenger car maintenance manual...
it lists toe in both straight and at full left and full right travel of the suspension..

these are

' toe in as adjusted ' --- 0 degrees 25 '

measured track difference angle
left hand lock -0 degrees 20'
right hand lock +0 degrees 10'

actual track difference angle
left hand lock - 0 degrees 45'
right hand lock -0 degrees 15'

like Scott said ... you do NOT WANT ANY TOE OUT...
so you need enough toe in to compensate for the cumulative slack in your tie rod ends, wheel bearings, steering arm , etc..

tangofox007 · #18 07-24-2011, 08:18 PM

Quote:

Originally Posted by RML

T Besides, the problem was there before and after the alignment.

Pulling can be due to a tire problem. It might be worthwhile to swap the front tires to the opposite sides and see if the problem follows.

leathermang · #19 07-24-2011, 08:33 PM

I suggested that in the first reply.....but MB shows rotation of tires front to back...

tangofox007 · #20 07-24-2011, 08:48 PM

Quote:

Originally Posted by leathermang

I suggested that in the first reply.....but MB shows rotation of tires front to back...

Rotation is one thing, troubleshooting is another.

RML · #21 07-24-2011, 08:56 PM

Quote:

Originally Posted by tangofox007

Pulling can be due to a tire problem. It might be worthwhile to swap the front tires to the opposite sides and see if the problem follows.

When I do a quick flinch of the steering wheel, it sways equaly to each side. And as far as wandering, to my perception, it does not favor one side to the other.

leathermang · #22 07-24-2011, 09:10 PM

MB is saying that the direction of rotation of the tires is supposed be kept the same... keep the tire on the same side of the car...
this has been standard procedure for decades....

Codifex Maximus · #23 07-24-2011, 09:17 PM

Quote:

Originally Posted by Army

Now there's another reason to buy paper instead of the CD...

They (MB) need to update the images on the CD with high-quality PNGs or something.

Until a couple weeks ago, my front end on my 300D was in terrible shape. Eating tires pretty badly. I finally got up the cash to go have it rebuilt. Turns out the front end was in excellent shape all save for a single bolt. The tech replaced the bolt and realigned the front end all for $60 USD.

Now she drives strait as an arrow.

Codifex Maximus · #24 07-24-2011, 09:21 PM

Quote:

Originally Posted by leathermang

MB is saying that the direction of rotation of the tires is supposed be kept the same... keep the tire on the same side of the car...
this has been standard procedure for decades....

Leather, that was true in times past due to the way radials were manufactured. You wouldn't want to run a tire in the opposite direction from the one it had been running in.

These days, I've been assured, that is not the case. I'm still a little leery though...

Question that the OP should probably be asking:
Is there a good front end man in my area?

Then, have him inspect my front end for me.

leathermang · #25 07-24-2011, 09:31 PM

That very well be true.....
but the safest thing would be to keep them on the same side like the FSM says.... and it is logical ...

tangofox007 · #26 07-24-2011, 09:35 PM

Quote:

Originally Posted by leathermang

MB is saying that the direction of rotation of the tires is supposed be kept the same... keep the tire on the same side of the car...

Just make sure you never drive in reverse!!! Your tires might not survive turning backwards.

Quote:

Originally Posted by leathermang

this has been standard procedure for decades....

More correctly, it was standard procedure decades ago.

leathermang · #27 07-24-2011, 09:41 PM

Quote:

Originally Posted by tangofox007

Just make sure you never drive in reverse!!! Your tires might not survive turning backwards.

I try to keep my speed under 60 when in reverse...
What is wrong with you ?
I am quoting the FSM....and logic....
there are no good reasons to introduce possible intervening variables into his diagnostics...

tangofox007 · #28 07-24-2011, 09:48 PM

Quote:

Originally Posted by leathermang

What is wrong with you ?

Do you really think that a short test drive with the tires reversed is going to hurt anything?

I am a big believer in the FSM, but a paper FSM doesn't update itself as the world changes. And MB doesn't make tires. I would follow the tire manufacturers recommendation over the FSM where tires are involved. And, from looking at the tire manufacturers' recommendations, it appears that the old "same side" rotation requirements have died a quiet death.

Quote:

Originally Posted by leathermang

there are no good reasons to introduce possible intervening variables into his diagnostics...

What's the alternative? Doing the same things over and over, expecting a different result?

If swapping a couple of wheels is too hard, I give up. Typing is too hard, too.

leathermang · #29 07-24-2011, 09:55 PM

It is not logical to introduce new variables into the test procedure... even if it might be just fine....

Show me where some steel belted tire makers SUGGEST switching sides in rotation .... as compared to saying ' it is ok '.....

Notice the OP's description of the symptoms...

Can you be SURE that switching them from one front to the other would result in identifiable change in symptoms ? It might still wander ... it might not exhibit Opposite wander from the original situation...and he did not say ' it pulls ' a certain direction..... then where are you ?
If you put them on the back though... and it stops the wander then you check for broken belts and such in the tires....

tangofox007 · #30 07-24-2011, 10:01 PM

Quote:

Originally Posted by leathermang

Can you be SURE that switching them from one front to the other would result in identifiable change in symptoms ?

There is no need to be SURE. We are just swapping tires, not doing a heart/lung transplant. The operation is completely reversible if it fails to produce worthwhile results.

Quote:

Originally Posted by leathermang

Show me where some steel belted tire makers SUGGEST switching sides in rotation .... as compared to saying ' it is ok '.....

http://www.goodyeartires.com/faqs/rotation/

http://www.michelinman.com/tire-care/tire-saving-tips/

http://www.aa1car.com/library/tire_rotation_bridgestone.pdf

http://www.kumhotireusa.com/Basics_TireRotation.aspx

http://www.agcoauto.com/content/news/p2_articleid/94